It's a tricky situation. On one hand, you can't help but have to use a bathroom sometimes when you're out, and it sucks that you'd have to pay for that, especially since you might not have any change, and then what would you do? And it just seems kind of vulgar/low-class to make people pay to use your toilet.
But on the other hand, having a public toilet requires maintenance costs... people can be filthy, so the bathrooms have to be constantly cleaned, among other costs, so it kind of makes sense to change for it, though IMO it makes less sense to charge actual patrons of your business, but I guess it's hard to distinguish who's a patron and who's not..